Analysis Summary
Notes:
- 1) No attempt has been made to eliminate the non-significant decimal places.
- 2) This batgrbproduct analysis is done using the HEASARC data.
- 3) This batgrbproduct analysis is using the flight position for the mask-weighting calculation.
==========================================================================
BAT GROUND-DETECTED GRB DATA PROCESSING REPORT
(This burst occurred during telescope slew)
Process Script Ver: batgrbproduct v2.46
Process Start Time: Tue Nov 11 10:53:32 EST 2014
Host Name: bat1
Current Working Dir: /local/data/bat1/alien/Swift_3rdBATcatalog/event/batevent_reproc/GRB081025
======================================================================
Trigger: 00035650 Segment: 186
BAT Trigger Time: 246615786.152
UTC: 2008-10-25T08:23:02.950 [includes UTCF correction]
Where From?: Ground analysis (best_duration.txt)
NOTE: BAT trigger time for ground-detected burst during slew is the T100 start time.
Refined Position: [ source = BAT mosaic image ]
RA: 245.296295991584 Dec: 60.4546109105949 [deg; J2000]
{ 16h 21m 11.1s , +60d 27' 16.6" }
+/- 0.857492708679 [arcmin] (estimated 90% radius based on SNR)
SNR: 37.8931133745
Angular difference between the analysis and refined position is Usage: arcmin
Partial Coding Fraction: Unavailable because the burst occurred during slew.
Duration
T90: 22.7600000202656 +/- 1.02964071782397
Measured from: 1.848
to: 24.608 [s; relative to TRIGTIME]
T50: 16.5399999916553 +/- 0.625664446951632
Measured from: 4.452
to: 20.992 [s; relative to TRIGTIME]
====== Table of the duration information =============================
Value tstart tstop
T100 25.172 0.000 25.172
T90 22.760 1.848 24.608
T50 16.540 4.452 20.992
Peak 1.000 3.340 4.340
====== Spectral Analysis Summary =====================================
Model : spectral model: simple power-law (PL) and cutoff power-law (CPL)
Ph_index : photon index: E^{Ph_index}
Ph_90err : 90% error of the photon index
Epeak : Epeak in keV
Epeak_90err: 90% error of Epeak
Norm : normalization at 50 keV in both the PL model and CPL model
Nomr_90err : 90% error of the normalization
chi2 : Chi-Squared
dof : degree of freedo
=== Time-averaged spectral analysis ===
(Best model with acceptable fit: PL)
Model Ph_index Ph_90err_low Ph_90err_hi Epeak Epeak_90err_low Epeak_90err_hi Norm Nomr_90err_low Norm_90err_hi chi2 dof
PL -1.029 -0.075 0.076 - - - 6.99e-03 -2.91e-04 2.90e-04 43.240 57
CPL -0.922 -0.140 0.268 553.740 -334.563 -553.740 7.77e-03 -9.89e-04 2.16e-03 43.310 56
=== 1-s peak spectral analysis ===
(Best model with acceptable fit: PL)
Model Ph_index Ph_90err_low Ph_90err_hi Epeak Epeak_90err_low Epeak_90err_hi Norm Nomr_90err_low Norm_90err_hi chi2 dof
PL -0.806 -0.141 0.145 - - - 1.84e-02 -1.49e-03 1.48e-03 66.770 57
CPL -0.805 -0.136 0.179 9999.360 -9999.360 -9999.360 1.85e-02 -1.54e-03 1.07e-02 66.790 56
=== Fluence/Peak Flux Summary ===
Model Band1 Band2 Band3 Band4 Band5 Total
15-25 25-50 50-100 100-350 15-150 15-350 keV
Fluence PL 1.45e-07 3.55e-07 6.97e-07 3.38e-06 1.88e-06 4.57e-06 erg/cm2
90%_error_low -1.27e-08 -1.86e-08 -3.14e-08 -3.49e-07 -8.22e-08 -3.64e-07 erg/cm2
90%_error_hi 1.32e-08 1.85e-08 3.12e-08 3.79e-07 8.23e-08 3.89e-07 erg/cm2
Peak flux PL 3.91e-01 5.96e-01 6.82e-01 1.49e+00 2.11e+00 3.16e+00 ph/cm2/s
90%_error_low -6.62e-02 -6.30e-02 -5.64e-02 -2.60e-01 -1.68e-01 -2.90e-01 ph/cm2/s
90%_error_hi 7.05e-02 6.21e-02 5.60e-02 2.96e-01 1.68e-01 3.04e-01 ph/cm2/s
Fluence CPL 1.42e-07 3.57e-07 7.01e-07 3.31e-06 1.88e-06 4.30e-06 erg/cm2
90%_error_low -1.65e-08 -1.91e-08 -3.50e-08 -1.21e-06 -8.64e-08 -9.58e-07 erg/cm2
90%_error_hi 1.32e-08 1.94e-08 3.80e-08 2.79e-07 8.32e-08 3.00e-07 erg/cm2
Peak flux CPL 3.90e-01 5.97e-01 6.80e-01 1.48e+00 2.12e+00 3.22e+00 ph/cm2/s
90%_error_low N/A N/A N/A N/A N/A -7.44e-01 ph/cm2/s
90%_error_hi N/A N/A N/A N/A N/A 2.87e-01 ph/cm2/s
======================================================================
Image
Note1: The mosaic image is made with timebin = 0.10 s; energybin = 15-350 keV
Note2: The mosaic image uses Galactic coordinate.
#RAcent DECcent POSerr Theta Phi Peak_Cts SNR Name 245.296 60.455 0.002 35.410 -88.420 0.084 37.893 UNKNOWN Image time interval: 0.000 to 25.172 [sec]
Light Curves
Note: The mask-weighted lightcurves have units of either count/det or counts/sec/det, where a det is 0.4 x 0.4 = 0.16 sq cm.
Best duration plot
Full-time range; 1 s binning
Other quick-look light curves:
- 64 ms binning (zoomed)
- 16 ms binning (zoomed)
- 8 ms binning (zoomed)
- 2 ms binning (zoomed)
- SN=5 or 10 s binning (full-time range)
- Raw light curve
Spectra
- 64 ms binning (zoomed)
- 16 ms binning (zoomed)
- 8 ms binning (zoomed)
- 2 ms binning (zoomed)
- SN=5 or 10 s binning (full-time range)
- Raw light curve
Spectra
Notes:
- 1) The fitting includes the systematic errors.
- 2) When the burst includes telescope slew time periods, the fitting uses an average response file made from multiple 5-s response files through out the slew time plus single time preiod for the non-slew times, and weighted by the total counts in the corresponding time period using addrmf. An average response file is needed becuase a spectral fit using the pre-slew DRM will introduce some errors in both a spectral shape and a normalization if the PHA file contains a lot of the slew/post-slew time interval.
- 3) For fits to more complicated models (e.g. a power-law over a cutoff power-law), the BAT team has decided to require a chi-square improvement of more than 6 for each extra dof.
Time averaged spectrum fit using the average DRM
Power-law model
Time interval is from 0.000 sec. to 25.172 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -1.02904 ( -0.0753727 0.0762856 ) Norm@50keV : 6.98669E-03 ( -0.000291331 0.000290181 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 43.24 using 59 PHA bins. # Reduced chi-squared = 0.7585 for 57 degrees of freedom # Null hypothesis probability = 9.109330e-01 Photon flux (15-150 keV) in 25.17 sec: 0.805751 ( -0.034611 0.034711 ) ph/cm2/s Energy fluence (15-150 keV) : 1.88262e-06 ( -8.21639e-08 8.23348e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.000 sec. to 25.172 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -0.921784 ( -0.0996094 0.308765 ) Epeak [keV] : 553.740 ( -715.575 -934.751 ) Norm@50keV : 7.77335E-03 ( -0.000667132 0.00247731 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 43.31 using 59 PHA bins. # Reduced chi-squared = 0.7734 for 56 degrees of freedom # Null hypothesis probability = 8.924478e-01 Photon flux (15-150 keV) in 25.17 sec: 0.803044 ( -0.036503 0.034849 ) ph/cm2/s Energy fluence (15-150 keV) : 1.87674e-06 ( -8.64464e-08 8.32065e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 3.340 sec. to 4.340 sec. Spectral model in power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -0.80617 ( -0.140903 0.144925 ) Norm@50keV : 1.83934E-02 ( -0.00148872 0.0014784 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 66.77 using 59 PHA bins. # Reduced chi-squared = 1.171 for 57 degrees of freedom # Null hypothesis probability = 1.763943e-01 Photon flux (15-150 keV) in 1 sec: 2.11352 ( -0.16781 0.16808 ) ph/cm2/s Energy fluence (15-150 keV) : 2.14408e-07 ( -1.83475e-08 1.84494e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 3.340 sec. to 4.340 sec. Spectral model in the cutoff power-law: ------------------------------------------------------------ Parameters : value lower 90% higher 90% Photon index: -0.805125 ( -0.138285 0.176548 ) Epeak [keV] : 9999.36 ( -9999.36 -9999.36 ) Norm@50keV : 1.85342E-02 ( -0.00152884 0.0106953 ) ------------------------------------------------------------ #Fit statistic : Chi-Squared = 66.79 using 59 PHA bins. # Reduced chi-squared = 1.193 for 56 degrees of freedom # Null hypothesis probability = 1.532859e-01 Photon flux (15-150 keV) in 1 sec: 2.11719 ( ) ph/cm2/s Energy fluence (15-150 keV) : 1.33854e-08 ( 0 0 ) ergs/cm2
Time-resolved spectra
Distribution
T90 vs. Hardness ratio plot
T90 = 22.76 sec. Hardness ratio (energy fluence ratio) = 1.96019887477
S(15-50 keV) vs. S(50-150 keV) plot
S(15-50 keV) = 5.000641e-07 S(50-150 keV) = 1.382534e-06
The dash-dotted line and the dashed line traces the fluences calculated from the Band function with Epeak = 15 and 150 keV, respectively. Both lines assume a canonical values of alpha = -1 and beta = -2.5.
Mask shadow pattern
Mask shadow pattern unavailable because this burst occurs during telescope slews.Spacecraft aspect plot
